core

#### Check Distance

The Check Distance box defines the distance past the theoretical hit location that the machine continues to search or check for the surface of the part. This distance is after it traverses the Prehit Distance value. The default value is zero.

- If this is zero, after the prehit distance, the machine searches to a maximum distance of three times the Prehit Distance value. For example:

A - The theoretical surface location. B - The prehit distance. C - The check distance it moves is three times the prehit.

- If this is a positive, non-zero number, after the prehit distance, the machine searches to a maximum distance of the Check Distance value. For example, if you specify a Check Distance of 2 the probe moves by a value of two units:

A - The theoretical surface location. B - The prehit distance. C - The check distance it moves is the specified Check Distance value, in this example, two units.

The Probe Readout window shows the probe location based on the probe's center. However, the machine uses the outer diameter of the probe to drive to the surface. This means the values in the Probe Readout always show a probe radius less than what you might expect when it moves to this distance.

The measurement units for the distance depends on the measurement system used for the part

The Edit window command line for this option reads:
CHECK/distance,percentage

Percentage Movement During Find Hole Operations

When defining the check distance for a Find Hole operation, you can tell PC-DMIS to move by a percentage of the check distance.

To do this:

1. Access the Edit window and place it in Command mode.

2. Click on the CHECK command in the Edit window.

3. Press the Tab key to move to the second number.

4. Type a new percentage value. The default value is 1 which means 100% of the check distance. Thus .1=10%, .2=20%, .3=30% and so on.

For example, in the following code, the .3 value represents 30% of the total check distance of twenty units:
CHECK/20,.3

For information on the Edit window command see "Check Distance" in the "Using the Edit Window". chapter.

For additional information on Find Hole, see the "Working with Contact Find Hole Properties" topic in the "PC-DMIS CMM" documentation.